Shoyo Roku (The Book of Serenity) This is the other great classic koan collection, along with the Mumonkan. One hundred cases, some of which show up in the Mumonkan as well, were reassembled (after being lost) by Wansong. This version does not contain anything other than the cases themselves nor does it acknowledge who the translator was. However, it can still serve a function. Thomas Cleary's translation (The Book of Serenity, Lindisfarne Press) is still the standard complete version in English.

Shaseki-shu : (Collection of Stone and Sand), written late in the thirteenth century by the Japanese Zen teacher Muju (the "non-dweller"), and from anecdotes of Zen monks taken from various books published in Japan around the turn of the 20th century. Over 100 translations here.

Zen Flesh, Zen Bones: by Paul Reps and Nygen Sensaki an online version of the stories under the title 101 Zen Stories. Does not include excerpts of the Mumonkan or the 10 Bulls, both of which are in the original book. The stories are not really koans in the classical sense although some can be used as koans to aid awakening. The stories come from the Collection of Stone and Sand (see above)

Zen KōanStudy Page : this is Matthew Ciolek's Virtual Library Zen koan page. It includes a reference list of koan commentaries, a variety of definitions and a bibliography of koan studies. Some of the commentaries have links to the appropriate site. This site is worth the time it takes to explore.

Koan Commentaries and Study

Carl Hooper: Koan Zen and Wittgenstein’s Only
Correct Method in Philosophy Koan Zen is a philosophical practice that bears a strong family resemblance to Wittgenstein’s approach to philosophy.Both koan Zen and Wittgenstein’s method set limits to the reach of philosophical discourse. Each rules metaphysical speculation out of bounds. Neither, however, represents a rejection of the metaphysical. Where Wittgenstein enjoins silence in the face of the unsayable, a silence that allows the metaphysical to show itself, koan Zen calls for concrete demonstrations of that which cannot be captured in rational discourse.Asian Philosophy
Vol. 17, No. 3, November 2007, pp. 283–292

John F. Fisher: An Analysis Of The Koans In The Mu Mon Kwan Fisher looks at the Mumonkan and breaks the koans down into catagories, finding that although the koans differ, the message is the same: "...the way to satori is not through dependence upon words, even if they be words of the Buddha or past Masters; however, one should not reject words, for, imperfect as they are, they are the only means we have of attaining enlightenment. They should use the words and ideas contained in the koans to reach satori, but they should never confuse the two. "

Kusumoto Bunyū: Zengo Nyūmon (An Introduction to Zen Words and Phrases) translated by Michael D Ruymar. This text consists of 100 words and phrases selected by Dr. Kusumoto for exegesis from a variety of sources, but particularly from classic kōan collections like the Blue Cliff Record, the Gateless Barrier, and the Book of Serenity, as well as from the collected writings or sayings of renowned Zen Masters from both China and Japan, like Zen Masters Linji and Dōgen, or, again, from the poetry of such as Han Shan (Cold Mountain) and others. A useful guide in conjunction with Victor Sogen Hori's Zen Sand: The Book of Capping Phrases for Koan Practice. (see below)

Victor Sogen Hori has written a book of capping phrases (jakugo) for koans. The introduction to the book , which discusses extensively the history of koans and jakugo, is available for free download here. Also, here you will find some personal background about how the book came about. Highly recommended.

Hajime Nakamura: The Non-Logical Character of Zen Nakamura sees koans as "paradoxes which transcend the opposites" where "human existence is implicitly expressed". Are koans really paradoxes?

James D. Sellmann & Hans Julius Schneider Liberating Language in Linji and Wittgenstein The aim of this paper is to explicate some unexpected and striking similarities and equally important differences between Wittgenstein's methodology and the approach of Chinese Chan or Japanese Zen Buddhism. "The Zen approach to life most definitely sheds some light on what Ludwig Wittgenstein was ‘pointing’ at or trying to show through his kōanic or kōan-like use of philosophical problems. Wittgenstein’s analysis provides a way for understanding what the Zen master is doing. "Asian Philosophy, Vol. 13, Nos. 2/3, 2003

Barry Stephenson: The Koan as Ritual Performance "Study of the Zen kōan tradition has been dominated by psychological and textual methods and theories. But kōans not only constitute a literary genre, they are part of the liturgical order of Zen Buddhism. In this article I argue that psychological and textual approaches offer a limited understanding of the ritual and performative contexts of kōan practice and, drawing on ritual and performance theory, develop an alternative approach to the kōan tradition."

Youru Wang: The Pragmatics of ‘Never Tell Too Plainly’: indirect communication in Chan Buddhism This is a philosophical investigation of the linguistic strategy of Chinese Chan Buddhism. It examines the underlying structure of Chan communication, which determines the Chan pragmatics of 'never tell too plainly' revealing what the Chan `special transmission’ means. This essay also investigates the different types of the Chan strategies of indirect communication, such as the use of paradoxical, tautological and poetic language, which best demonstrate the principle of 'never tell too plainly'. from Asian Philosophy, Vol. 10, No.1, 2000